A large river plays many important roles in the water cycle. In some areas, rivers experience seasonal freezing where varying amounts of the upper portion of the water in the river freezes.

Question

How would the complete freezing of the upper 30 cm of water in the river effect the area’s water cycle?
Responses
A There would be more water runoff entering the river.There would be more water runoff entering the river.
B There would be no water evaporation leaving the river.There would be no water evaporation leaving the river.
C There would be more precipitation in the area due to excessive condensation.There would be more precipitation in the area due to excessive condensation.
D There would be no change in the area’s water cycle.

Answer 1

The correct response would be:

B There would be no water evaporation leaving the river.

If the upper 30 cm of water in the river completely freezes, the surface layer is effectively sealed off from the atmosphere, preventing evaporation from occurring. This would affect the water cycle in the area by limiting the amount of water vapor that could be released into the atmosphere from that river section during freezing conditions. Options A and C do not relate directly to the immediate consequences of freezing, and option D is incorrect because freezing would indeed change the dynamics of the water cycle in that area.